Field devices, which serve to register and/or influence process variables, are often applied in process as well as manufacturing, automation technology. Measuring devices, such as, for example, fill level measuring devices, flow measuring devices, pressure and temperature measuring devices, pH measuring devices, conductivity measuring devices, etc., serve to register the corresponding process variables, fill level, flow, pressure, temperature, pH value, or conductivity. Actuators, such as valves or pumps, are used to influence process variables, e.g. the flow of a liquid in a pipeline or the fill level of a medium in a container is changed via the actuator. Thus, the term ‘field devices’ subsumes all types of measuring devices and actuators in connection with the invention.
Additionally, all devices, which are applied near to the process and which deliver or process information relevant to the process, are also referred to as field devices in relation to the invention. Besides the measuring devices/sensors and actuators named above, units such as e.g. remote I/Os, gateways, linking devices and wireless adapters or radio adapters, which are directly connected to a fieldbus and which serve for communication with a superordinated unit, are generally also referred to as field devices. A large number of such field devices are produced and sold by the Endress +Hauser group of companies.
In modern industrial plants, communication between at least one superordinated control unit and field devices occurs, as a rule, via a bus system such as, for example, Profibus® PA, Foundation Fieldbus® or HART®. The bus systems can be wireless as well as hardwired. The superordinated control unit serves for process control, process visualization, process monitoring as well as for start up and servicing of the field devices and is also referred to as a configuration/management system.
The integration of field devices in configuration or management systems occurs via device descriptions, which ensure that the superordinated control units can detect and interpret the data delivered by the field devices. As a rule, the device descriptions for each field device type or for each field device type in different applications are provided by the pertinent device manufacturer. In order to enable the integration of field devices into different fieldbus systems, different device descriptions must be created for different fieldbus systems. Thus there are device descriptions for HART, Fieldbus Foundation and Profibus, to name just a few examples. The number of device descriptions is very large;—this is a result of the large number of different field devices or field device types in different applications and bus systems.
For the purpose of creating a universal description language for field devices, Fieldbus Foundation (FF), the HART Communication Foundation (HCF) and the Profibus User Organization (PNO) have created a unified electronic device description language (Electronic Device Description Language EDDL). The EDDL or the corresponding Electronic Device Description EDD is defined in the standard, IEC 61804-2.
Becoming ever more important in automation technology is the topic of industrial Ethernet. Examples of industrial Ethernet include: HSE, ControlNet, Industrial IP, Profi-Net, HART UDP/TCP, . . . . Field devices, which are connected to a superordinated control unit via an industrial Ethernet, also usually make use of a web server. This web server enables servicing, thus especially configuring, parametering or diagnosing of a field device, by means of a Web browser. In principle, the servicing of field devices is only possible online via a service unit connected, or connectable, to the field device. Until now, no method has been known as to how an offline field device, thus without integration into the industrial Ethernet, can be serviced.
Besides the device descriptions described above, so called Device Type Managers (DTM) or device managers or device drivers are applied; these require an FDT frame as a runtime environment. DTMs serve for comprehensive servicing of field devices and correspond to the FDT—Field Device Tool—specification. The FDT specification representing the industrial standard corresponds to an interface specification and was developed by PNO—Profibus User Organization—in cooperation with the ZVEI—Zentralverband Elektrotechnik und Elektroindustrie (German Electrical and Electronics Industry.) The respectively current FDT specification is obtainable from the ZVEI, the PNO, or the FDT Group.
In order to be able to utilize the device descriptions comprehensively in FDT environments or also in FDI environments, the device descriptions must be appropriately expanded so that they can perform e.g. also an offline parametering, or offline configuration and uploading/downloading. For this, it is necessary to adapt all device descriptions already present and to expand all device descriptions relative to the functions mentioned above. Correspondingly equipping the extensive device driver libraries is associated with an extremely high developmental effort.